Multimedia apparatus and synchronization method thereof

ABSTRACT

A multimedia apparatus and a synchronization method thereof are provided. The multimedia apparatus includes a video output unit which outputs a video, and a control unit which transmits an audio signal to the external device through the communication module and operates the video output unit to display a video corresponding to the audio signal by delaying the video based on delay information received from the external device through the communication module.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Korean Patent Application No.10-2007-0119817, filed on Nov. 22, 2007 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Apparatuses and methods consistent with the present invention relate toa multimedia device and a synchronization method thereof, and moreparticularly, to synchronizing audio signals and video signals whenreproducing images.

2. Description of the Related Art

As multimedia technology has developed, multimedia apparatuses forsupporting diverse functions using a single device have been introduced.Such multimedia apparatuses provide not only audio and video recordingand playback functions, but also data storage, message transmission, andcall functions, such as calling mobile phones. Examples of multimediaapparatuses for recording and reproducing images and broadcast signalsreceived from broadcast stations include a digital television (DTV), aportable multimedia player (PMP), a camcorder, a digital camera, adigital video disc (DVD) player, a set-top box (STB), and a mobilephone.

When a related art multimedia apparatus communicates with a headsetusing the Bluetooth protocol, the time that video is reproduced isdifferent from the time that audio is reproduced by the headset.Specifically, since there is a delay between the time an audio signal istransmitted from the multimedia apparatus and the time the signal isoutput through a speaker of the headset, the audio signal and acorresponding video signal are not synchronized. In particular, if abuffer provided by the headset is large, the delay is greater, so thesynchronization difference between a video signal reproduced by themultimedia apparatus and an audio signal reproduced by the headsetincreases, causing inconvenience to the user.

Therefore, there is a need for apparatuses and methods for synchronizingaudio signals and video signals when a multimedia apparatus reproducesimages.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention address at least theabove problems and/or disadvantages and other disadvantages notdescribed above. Also, the present invention is not required to overcomethe disadvantages described above, and an exemplary embodiment of thepresent invention may not overcome any of the problems described above.

An aspect of the present invention provides a multimedia apparatus whichis capable of outputting synchronized audio signals and video signals byextracting delay information by analyzing a service record acquiredusing the Bluetooth protocol and synchronizing the audio signals andvideo signals based on the extracted delay information, and asynchronization method thereof

Another aspect of the present invention provides a multimedia apparatuswhich is capable of outputting synchronized audio signals and videosignals using delay information acquired from an external device, and asynchronization method thereof

According to an exemplary aspect of the present invention, there isprovided a multimedia apparatus, including a communication module whichis connected to an external device for wireless communication, a videooutput unit which outputs a video, and a control unit which transmits anaudio signal to the external device through the communication module,and operates the video output unit to display a video corresponding tothe audio signal by delaying the video based on delay informationreceived from the external device through the communication module.

The delay information may be contained in a Reserved for Future Addition(RFA) area of the service record received from the external device, andthe control unit delays the video for a delay time contained in thedelay information acquired from the RFA area, and then outputs thedelayed video to the video output unit.

The delay information may refer to a data set in the 4^(th) to 15^(th)bits of the RFA area, and the control unit may calculate the delay timebased on the data set in the 4^(th) to 15^(th) bits of the RFA area, anddelay the video based on the calculated delay time.

At least one bit of the 4^(th) to 15^(th) bits of the RFA area may beused to set data indicating a delay unit, and the remaining bits exceptfor the at least one bit may be used to set data indicating the delaytime.

The service record may be contained in an advanced audio distributionprofile (A2DP) which is used in Bluetooth communication.

The Bluetooth module may acquire the service record by Bluetoothcommunication with the external device using a service discoveryprotocol (SDP).

According to another exemplary aspect of the present invention, there isprovided a synchronization method of a multimedia apparatus, the methodincluding receiving delay information by wireless communication with anexternal device, and transmitting an audio signal to the externaldevice, and displaying a video corresponding to the audio signal bydelaying the video based on the delay information received from theexternal device.

The wireless communication may be Bluetooth communication, and the delayinformation may be contained in a service record received from theexternal device.

The delay information may be contained in an RFA area of a packetreceived from the external device, and in the delay operation, the videomay be delayed for a delay time contained in the delay informationacquired from the RFA area, and then output.

The delay information may refer to data set in the 4^(th) to 15^(th)bits of the RFA area, and in the delay operation, the delay time may becalculated based on the data set in the 4^(th) to 15^(th) bits of theRFA area, and the video may be delayed based on the calculated delaytime.

At least one bit of the 4^(th) to 15^(th) bits of the RFA area may beused to set data indicating a delay unit, and the remaining bits exceptfor the at least one bit may be used to set data indicating the delaytime.

The service record may be contained in an advanced audio distributionprofile (A2DP) using Bluetooth communication.

The wireless communication may be Bluetooth communication, and in thereceiving operation, the service record may be acquired by Bluetoothcommunication with the external device using a service discoveryprotocol (SDP).

According to another exemplary aspect of the present invention, there isprovided an audio output apparatus, including an interface unit whichreceives an audio signal from an external device, and a control unitwhich sets delay information based on the period of time taken to outputthe audio signal.

The period of time taken to output the audio signal may indicate aperiod of time from when the audio signal is received until the audiosignal is output, and the control unit may measure the period of timefrom when the audio signal is received until when the audio signal isoutput, and set the delay information based on the measured period oftime.

The control unit may set the delay information, and transmit the setdelay information to the external device through the interface unit.

The delay information may include at least one of a delay time and adelay unit.

According to another exemplary aspect of the present invention, there isprovided a multimedia apparatus, including a communication module whichis connected to an external device for wireless communication, an audiooutput unit which outputs an audio signal, and a control unit whichtransmits a video signal to the external device through thecommunication module, and operates the audio output unit to display anaudio signal corresponding to the video signal by delaying the audiosignal based on delay information received from the external devicethrough the communication module.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects of the present invention will be moreapparent by describing certain exemplary embodiments of the presentinvention with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram of a multimedia apparatus according to anexemplary embodiment of the present invention;

FIG. 2 is a block diagram of a headset according to an exemplaryembodiment of the present invention;

FIG. 3 is a drawing illustrating an example of the construction of aservice record according to an exemplary embodiment of the presentinvention;

FIG. 4 is a drawing illustrating an example of an RFA area in whichdelay information is set according to an exemplary embodiment of thepresent invention; and

FIG. 5 is a flow chart illustrating a method for synchronizing audio andvideo signals between a multimedia apparatus and a headset according toan exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Certain exemplary embodiments of the present invention will now bedescribed in greater detail with reference to the accompanying drawings.

In the following description, like drawing reference numerals are usedfor like elements, even in different drawings. The matters defined inthe description, such as detailed construction and elements, areprovided to assist in a comprehensive understanding of the invention.However, the present invention can be practiced without thosespecifically defined matters. Also, well-known functions orconstructions are not described in detail since they would obscure theinvention with unnecessary detail.

FIG. 1 is a block diagram of a multimedia apparatus according to anexemplary embodiment of the present invention.

With reference to FIG. 1, the multimedia apparatus 100 according to anexemplary embodiment of the present invention includes a broadcastreceiving unit 110, an audio/video (A/V) processing unit 120, an audiooutput unit 130, a video output unit 140, a storage unit 150, aBluetooth module 160, and a control unit 170.

The broadcast receiving unit 110 receives and demodulates a broadcastfrom a broadcast station or a satellite via a wire connection orwirelessly. The broadcast receiving unit 110 also receives content froma broadcast station or a satellite. The content includes moving images,still images, broadcast programs, or audio data.

The A/V processing unit 120 performs video decoding, video scaling oraudio decoding of broadcast signals output from the broadcast receivingunit 110. Subsequently, the A/V processing unit 120 transmits videosignals to the control unit 170, and audio signals to the audio outputunit 130 and the control unit 170.

The audio output unit 130 outputs the audio signals received from theA/V processing unit 120 through a speaker.

The video output unit 140 outputs video received from the control unit170 on a display, or outputs the video to an external device to whichthe multimedia apparatus 100 is connected through an external outputterminal.

The storage unit 150 stores broadcast data processed by the A/Vprocessing unit 120 or programs, software code, instructions and thelike required to control the elements constituting the multimediaapparatus 100.

The Bluetooth module 160 converts audio signals received from thecontrol unit 170 to a format for Bluetooth communication, and convertsdata received from the headset 200 to a format capable of beingprocessed by the multimedia apparatus 100.

The control unit 170 transmits audio signals received from the A/Vprocessing unit 120 to the Bluetooth module 160, and extracts delayinformation from a service record received from the headset 200 usingthe Bluetooth module 160. The control unit 170 delays video signalsoutput from the A/V processing unit 120 according to a delay timecontained in the extracted delay information, and displays the delayedvideo signals through the video output unit 140.

The delay information includes at least one of a delay time and a delayunit, which is a unit of the delayed time. The service record iscontained in an advanced audio distribution profile (A2DP) which is aprofile used for transmission and reception of audio data in Bluetoothcommunication. The multimedia apparatus 100 performs Bluetoothcommunication with the headset 200 using a service discovery protocol(SDP).

FIG. 2 is a block diagram of a headset according to an exemplaryembodiment of the present invention.

With reference to FIG. 2, the headset 200 includes an interface unit210, a control unit 230, a buffer 250, and an audio output unit 270. Theheadset 200 supports Bluetooth communication, and performs wirelesscommunication with the multimedia apparatus 100.

The interface unit 210 receives audio signals from the multimediaapparatus 100 using Bluetooth communication. The multimedia apparatus100 performs Bluetooth communication with the headset 200 using an SDP.

The control unit 230 buffers the received audio signals using the buffer250. The control unit 230 measures the time from the time that the audiosignals are received until the time that the audio signals are outputfrom the audio output unit 270, and generates delay information based onthe measured time. As explained in greater detail below with referenceto FIGS. 3 and 4, the control unit 230 contains the delay information ina Reserved for Future Addition (RFA) area contained in a service record.The delay information includes at least one of a delay time and a delayunit which may include at least one of seconds, milliseconds,microseconds, and nanoseconds.

More specifically, the control unit 230 sets the delay information inbits 4 to 15 of the service record which is predetermined as an RFA asshown in FIG. 3.

For example, if the time from when the audio signals are received untilthe audio signals are output from the audio output unit 270 is measuredat 10 seconds, the control unit 230 sets delay information including adelay time of 10 seconds and a delay unit “seconds” in the RFA area.More specifically, the control unit 230 sets the delay time as “1010”,which is a delay time of 10 converted into binary code, and sets thedelay unit as “00”.

As shown in FIG. 4, the control unit 230 uses bits 4 and 5 as the bitsfor the delay unit, and uses bits 6 to 15 as the bits for the delaytime. That is, the control unit 230 sets the delay time by setting bits15 to 10, bit 8, and bit 6 to “0” and bits 7 and 9 to “1”. In addition,the control unit 230 sets the delay unit by setting bits 5 and 4 to “0”.The delay unit is set as shown in Table 1.

TABLE 1 Bit 5 Bit 4 Value 0 0 sec (second) 0 1 msec (millisecond) 1 0μsec (microsecond) 1 1 ns (nanosecond)

The audio output unit 270 outputs the audio signals from the buffer 250through a speaker mounted in the headset 200.

FIG. 5 is a flow chart illustrating a method for synchronizing audiosignals and video signals between a multimedia apparatus and a headsetaccording to an exemplary embodiment of the present invention.

With reference to FIG. 5, the multimedia apparatus 100 transmits to theheadset 200 an audio signal corresponding to a video signal to bedisplayed (S510). The multimedia apparatus 100 transmits the audiosignal to the headset 200 by Bluetooth communication using an SDPprotocol.

The control unit 230 of the headset 200 measures from the time that theaudio signal is received until the time that the audio signal is outputto the speaker mounted in the headset 200 (S520).

Subsequently, the control unit 230 of the headset 200 generates delayinformation based on the measured time. The delay information mayinclude a delay time and a delay unit, which may include at least one ofseconds, milliseconds, microseconds, and nanoseconds.

In greater detail, the control unit 230 sets the delay time byconverting the measured time to binary code, and sets the unit of themeasured time as a delay unit.

Subsequently, the control unit 230 sets the generated delay informationin a service record (S540). The service record is contained in an A2DP,which is a profile used for transmission and reception of audio data.

More specifically, the control unit 230 sets the generated delayinformation in the RFA area contained in the service record, wherein thecontrol unit 230 allocates two bits of the RFA area to a delay unit, andthe remaining bits of the RFA area to a delay time. The RFA areaincludes bits 4 to 15.

The interface unit 210 of the headset 200 transmits the service recordto the multimedia apparatus 100 using the Bluetooth communication(S550).

The control unit 170 of the multimedia apparatus 100 extracts the delayinformation contained in the received service record (S560).

Subsequently, the control unit 170 delays and outputs the video signalbased on the extracted delay information (S570).

For example, if the delay time in the extracted delay information is 10seconds, the control unit 170 delays a video signal corresponding to theaudio signal transmitted in operation S510 for 10 seconds, and thenoutputs the video signal. Accordingly, the control unit 230 maysynchronize the video signal output from the multimedia apparatus 100with the audio signal output from the headset 200.

In a multimedia apparatus and a synchronization method thereof accordingto an exemplary embodiment, the delay information includes a delay timeand a delay unit, but the delay information is not limited thereto. Inanother exemplary embodiment, the delay unit may be predetermined, sothat the delay information may include only a delay time. That is, the12 bits of the RFA area may be used as the bits for setting the delaytime.

In a headset according to an exemplary embodiment of the presentinvention, a delay unit accounts for 2 bits of the RFA area and a delaytime accounts for 10 bits, but the present invention is not limited tosuch a configuration. A delay unit may account for 1 bit or more than 2bits. The remaining bits except for the bits allocated to the delay unitmay be used for setting the delay time.

In a headset according to an exemplary embodiment of the presentinvention, bits 4 and 5 of the RFA area are used to set a delay unit andbits 6 to 15 are used to set a delay time, but the present invention isnot limited to such a configuration. One or more of bits 4 to 15 may beused to set a delay unit. The remaining bits other than the bits forsetting the delay unit may be used to set a delay time.

In a multimedia apparatus and a synchronization method thereof accordingto an exemplary embodiment of the present invention, the multimediaapparatus transmits data to and receives data from a headset usingBluetooth communication, but the communication means is not limitedthereto. The multimedia apparatus may transmit data to and receive datafrom the headset by wireless communication.

In a multimedia apparatus and a synchronization method thereof accordingto an exemplary embodiment of the present invention, the multimediaapparatus acquires delay information from a service record received froma headset, but the present invention is not limited to such aconfiguration. The multimedia apparatus may acquire the delayinformation from a packet received from the headset other than theservice record. That is, the delay information may be contained in apacket received from the headset other than the service record.

In a headset according to an exemplary embodiment of the presentinvention, a delay time is calculated by measuring from the time that anaudio signal is received from a multimedia apparatus until the time thatthe audio signal is output, but it is not limited thereto. The delaytime may be calculated as the period of time taken to output the audiosignal by the headset.

That is, the delay time may refer to the time from when an audio signalis input from one of the elements of the headset until the audio signalis output from another element. In this case, a control unit maycalculate the time from when an audio signal is input to a buffer untilthe audio signal is output from the buffer. That is, the control unitmay calculate the delay time by measuring the time during which an audiosignal is input to and output from one of the elements of the headset.

In a multimedia apparatus and a synchronization method thereof accordingto an exemplary embodiment of the present invention, the multimediaapparatus delays an image signal based on delay information of an audiosignal, but the present invention is not limited thereto. The multimediaapparatus may delay an audio signal corresponding to an image signalbased on the delay information.

The foregoing exemplary embodiments are merely exemplary and are not tobe construed as limiting the present invention. The present teaching maybe readily applied to other types of apparatuses. Also, the descriptionof the exemplary embodiments of the present invention is intended to beillustrative, and not to limit the scope of the claims, and manyalternatives, modifications, and variations will be apparent to thoseskilled in the art.

As may be appreciated from the above description, image signals outputfrom a multimedia apparatus may be synchronized with audio signalsoutput from a headset by delaying image signals based on delayinformation extracted from a received service record.

Audio signals and image signals may be synchronized using delayinformation acquired from an external device.

1. A multimedia apparatus comprising: a communication module which iscommunicably linked to an external device for wireless communication; avideo output unit which outputs a video; and a control unit whichtransmits an audio signal to the external device through thecommunication module and operates the video output unit to display avideo corresponding to the audio signal by delaying the video based ondelay information received from the external device through thecommunication module.
 2. The multimedia apparatus of claim 1, whereinthe delay information is contained in a service record received from theexternal device via Bluetooth communication.
 3. The multimedia apparatusof claim 2, wherein the delay information is contained in a reserved forfuture addition (RFA) area of the service record, and wherein thecontrol unit delays the video for a delay time contained in the delayinformation acquired from the RFA area and outputs the delayed video tothe video output unit.
 4. The multimedia apparatus of claim 3, whereinthe delay information is recorded as a data set in bits 4 to 15 of theRFA area, and wherein the control unit calculates the delay time basedon the data set and delays the video based on the calculated delay time.5. The multimedia apparatus of claim 3, wherein at least one bit of bits4 to 15 of the RFA area is used to set data indicating a delay unit, andwherein bits of the bits 4 to 15, other than the at least one bit areused to set data indicating the delay time.
 6. The multimedia apparatusof claim 1, wherein the delay information is contained in a servicerecord which the communication module acquires from the external devicevia an advanced audio distribution profile (A2DP) which is used inBluetooth communication.
 7. The multimedia apparatus of claim 1, whereinthe communication module acquires a service record comprising the delayinformation via Bluetooth communication with the external device using aservice discovery protocol (SDP).
 8. A synchronization method for amultimedia apparatus, the method comprising: receiving delay informationvia wireless communication from an external device; transmitting anaudio signal to the external device; and displaying a videocorresponding to the audio signal by delaying the video based on thedelay information received from the external device.
 9. The method ofclaim 8, wherein the receiving the delay information comprises:receiving a service record from the external device via Bluetoothcommunication, wherein the service record comprises the delayinformation.
 10. The method of claim 8, wherein the receiving the delayinformation comprises receiving a packet from the external device,wherein the packet comprises a reserved for future addition (RFA) area,comprising the delay information, the method further comprising:delaying the video for a delay time contained in the delay informationacquired from the RFA area; and outputting the delayed video.
 11. Themethod of claim 10, wherein the delay information is recorded as a dataset in bits 4 to 15 of the RFA area, and wherein the delaying the videocomprises: calculating the delay time based on the data set; anddelaying the video based on the calculated delay time.
 12. The method ofclaim 11, wherein at least one bit of the bits 4 to 15 of the RFA areais used to set data indicating a delay unit, and bits of the bits 4 to15, other than the at least one bit are used to set data indicating thedelay time.
 13. The method of claim 8, wherein the receiving the delayinformation comprises: receiving a service record via an advanced audiodistribution profile (A2DP) which is used in Bluetooth communication.14. The method of claim 8, wherein the receiving the delay informationcomprises: acquiring a service record via Bluetooth communication withthe external device using a service discovery protocol (SDP).
 15. Anaudio output apparatus comprising: an interface unit which sends to andreceives from an external device an audio signal; and a control unitwhich sets delay information based on a period of time taken to outputthe audio signal by the external device.
 16. The audio output apparatusof claim 15, wherein the period of time taken to output the audio signalindicates a period of time from when the audio signal is received by theexternal device until the audio signal is output by the external device,and wherein the control unit measures the period of time from when theaudio signal is received until the audio signal is output, and sets thedelay information based on the measured period of time.
 17. The audiooutput apparatus of claim 15, wherein the control unit sets the delayinformation and transmits the set delay information to the externaldevice through the interface unit.
 18. The audio output apparatus ofclaim 15, wherein the delay information comprises at least one of adelay time and a delay unit.
 19. A multimedia apparatus comprising: acommunication module which is connected to an external device forwireless communication; an audio output unit which outputs an audiosignal; and a control unit which transmits a video signal to theexternal device through the communication module and operates the audiooutput unit to output the audio signal corresponding to the video signalby delaying the audio signal based on delay information received fromthe external device through the communication module.